- "There won't be a bloodbath. At the very least, I want to believe in that hope."
—Momoka in the manga Chapter 28
As shown in the manga, chapters 27 and 28, Momoka arrived at the Borderland with Asahi and were immediately escorted by the local chief dealer to the observation center which is kept secret from the player. The 2 girls were briefed with the rules of dealers and their relationship with the players, including that a player's victory means the death of the dealer of that game. In the dealers' center, Momoka heard of a rumor about leaving the Borderland after the dealer has successfully caused 100 players' death, which was never verified.
Disgusted by the other dealers' corruption and their willingness to root for player deaths, Momoka volunteered to participate in a extreme game setup in the Beach society which required one dealer to commit suicide and another dealer to assist with preparation. Momoka hoped that succeeding her last mission would stack their accumulated players' death to 100 and allow Asahi to return to the original world. Keiichi Kuzuryū, the King of Diamonds, finds her at the Beach and reveals his identity as a citizen to her. He asks her why she has offered her own life to serve the role of the Witch and she responds that it is for the sake of her ideal - that human hearts are beautiful and human lives are precious. On the other hand, Momoka also hoped that the players could calmly see through the trick of the game, as she was fed up with the ongoing dealer-player massacre and everyone losing their humanity in Borderland.
- The name Momoka means "bud, sprout" (萌) (mo) and "flower, blossom" (花) (ka).
- Momoka's surname Inoue means "well, mine shaft, pit" (井) (i) and "above, top, upper" (上) (ue).